On phenomena in ionized gases
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- A Spiral Microstrip-line Microwave Resonant Probe- for Measurement of Plasma Density
- Emergency critical care medicine for brain disease by irradiation / inhalation of atmospheric pressure plasma flow
- Excitation, recombination and dissociation of molecular cations by electron-impact in cold plasmas: Application to H 2 +
- Measurements of nitrogen and oxygen atom density in N 2 /Ar sputtering
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2. Model description To describe the electrons, the continuity, electron energy balance
equation and
drift-diffusion approximation were applied. Two-term Boltzmann approximation EEDF was applied to the model. The ion was calculated by adapting the continuity equation and the drift-diffusion approximation. The ion temperature and mobility were computed using the ion energy distribution functions (IEDFs). In addition, the energy and mobility of neutral species were considered. A block diagram for calculation of
Fig. 1. A block diagram for calculations of the ion temperature, mobility and the EEDF.
the ion temperature, mobility and the EEDF is shown Fig. 1.
3. References [1] L. L. Alves, L. Marques, Plasma phys. Control. Fusion. 54 (2004) 124012. [2] J. van Dijk, G. M. W. kroesen, A. Bogaerts, J. Phys D: Appl. Phys. 42 (2009) 190301. Topic number: 5 160
XXXIII ICPIG, July 9-14, 2017, Estoril/Lisbon, Portugal
A Spiral Microstrip-line Microwave Resonant Probe-
Ying-Chieh. Wu, and Keh-Chyang Leou Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan
In this study, a microwave probe (spiral probe, SP) based on a spiral shaped resonant structure is developed for plasma density measurement. The probe structure is a shorted microstrip transmission line operated at half-wavelength resonance. The characteristics of the probe is investigated by employing three dimensional electromagnetic numerical simulation anal ysis
(HFSS, ANSYS Corp) where the plasma is treated as a dielectric with dielectric functions determined by plasma density, microwave frequency and collision frequency of electrons. In the simulation, the resonance frequency is extracted from the reflection spectrum. Simulation results show that a monotonic increase of the resonant frequency with the plasma density.
The plasma density is one of the key parameters controlling the characteristics of plasma based processes. Thus, a non-invasive sensor, e.g., microwave-based ones, for monitoring, or even feedback control of the plasma density of plasma tools is highly desirable. One popular approach is the resonant-type microwave sensors, where a resonant structure is often employed and the plasma density is determined by the shift of the resonance frequency[1-3]. In our previous work, we have demonstrated a microstrip line microwave interferometer for monitoring of plasma density in plasma tools. In this study, a plasma density probe based on a spiral shaped microstrip microwave resonator, spiral probe (SP), is proposed. The structure of the probe and the measurement system are illustrated in Fig. 1. The probe is constructed by a shorted micro-strip transmission line operated at the
half-wavelength resonance.[4]
characteristics of the probe have been investigated by numerical analysis u sing the High Frequency Structure Simulator (HFSS)[5].
Fig. 1. Structure of Spiral-probe and experimental setup.
2. Simulation result Figure. 2. shows the electric field distribution at the resonance for plasma density of 5x10
10 cm -3 , illustrating
the characteristics of half-wave resonance. Figure 3 depicts the microwave reflection spectra for different plasma densities, along with
the dependence of the resonance frequencies on the plasma densities, showing a monotonic increase of the resonance frequencies with the plasma densities, as expected.
Fig. 2. The electric field distribution at resonance (2.71 GHz) for plasma density of 5x10 10 cm
. 1.0
1.5 2.0
2.5 3.0
3.5 -6 -5 -4 -3 -2 -1 0 Reflec tion(dB) Frequency [GHz] Vacuum 1x10
10 cm
-3 3x10
10 cm
-3 5x10
10 cm
-3 7x10
10 cm
-3 9x10
10 cm
-3 Fig. 3. HFSS simulation results: (a) microwave reflection spectra for different plasma densities, and (b) resonance frequency v.s. plasma density.
[1] M. Lapke, et al., Plasma Sources Sci. Technol., vol. 20, 2011. [2] R. B. Piejak, et al., Appl. Phys. vol. 95, 2004. [3] T. Shirakawa and H. Sugai, " Japan. J. Phys 32, pp. 5129, 1993. [4] A. Pandey, et al., Appl. Phys. vol. 104, 2014. [5] C. H. Hsieh, et al., Plasma Sources Sci. Technol. vol. 24, 2015.
Topic number: 6 0 2 4 6 8 10 1.8 2.0
2.2 2.4
2.6 2.8
3.0 3.2
3.4 Freque
ncy (GH
z) Plasma density (x10 10 cm
) 161
XXXIII ICPIG, July 9-14, 2017, Estoril/Lisbon, Portugal
Emergency & critical care medicine for brain disease by irradiation / inhalation of atmospheric pressure plasma flow
T. Hirata 1 , C. Kobayashi 1 , H. Watanabe 1 , S. Matsuda 1 , S. Wakita 1 , A. Mori 1 , Y. Kudo 2 , M. Iwashita 3
1 Department of Medical Engineering, Tokyo City University, Tokyo 158-8557, Japan 2 Department of Obstetrics and Gynecology, Hiroshima University, Hiroshima 734-8551, Japan 3 Department of Obstetrics and Gynecology, Kyorin University, Tokyo 181-8611, Japan
We performed to clarify the healing mechanism by which the irradiation / inhalation using atmospheric pressure (APP) plasma source promotes disease treatments such as burn healing, lung / heart disease treatment, bone regeneration, and cancer treatment. In this paper, the targeted disease treatment is functional recovery of hypoxic ischemic encephalopathy (HIE) by plasma inhalation.
Atmospheric pressure plasma
(APP) are
indispensable for
sterilizing, disinfecting, decomposing hazardous materials, and modifying material surfaces. Clarifying the mechanisms of plasma technologies that are used in practical applications is of critical importance. Against this background, we are trying to clarify the healing mechanism by which the APP inhalation promotes disease treatments. [1-3] The APP reactor with a coaxial structure is composed of a tungsten wire applied the high voltage inside a glass capillary that is surrounded by a grounded tubular electrode. The following conditions were applied pulse voltage: 5-8 kV; frequency: 1-5 kHz; helium (He) gas flow rate: 1 L/min; plasma irradiation time: 60-120 s. The hypoxic ischemic encephalopathy (HIE) is a condition in which the brain does not receive enough oxygen. Although any injury and many health conditions can cause a lack of oxygen to the brain, there is no cure for HIE. We accomplished the experiment concerning the functional recovery of HIE by APP inhalation. The rat HIE model used here involved ligating the common carotid artery with 3-0 silk to induce ischemia in the brain. The 7-day-old rats were allowed to recover for an hour and placed for 2 h in the infant incubator for hypoxia (oxygen (O 2 ): 8 %,
temperature: 37°C).
HIE model
rats were
anesthetized with sevoflurane, nitrous oxide (N 2 O), and O 2 using an anesthesia device with a mechanical respirator. The 3-week-old rat HIE model were done the plasma inhalation for two weeks. The experimental conditions of the plasma inhalation are follows; Inhalation-1: plasma including O 2 gas and Inhalation-2: plasma including O 2 + N 2 O gas. The rat’s head and the brain were diagnosed by using X-ray computed tomography (CT). Here, the CT scanner for experimental animals (Latheta LCT-200, Hitachi, Ltd.) was used for the rat’s head imaging. According to the CT images of rat’s brain, left brain in case of the Inhalation-1 is larger than that of Inhalation-2. The aneurysm, cerebral ischemia, and intricately shaped blood vessels were confirmed to the left brain. Especially, the cerebral ischemia makes a further trouble progressed so that not only causing the organization trouble at the cell level but also a rapid oxygen supply may generate a free radical such as super-oxides (OZ). The APP including N 2 O gases has the possibility of influencing the cerebral blood vessel. In addition, the condition of the cerebral ischemia is reported to be ameliorable by the promotion of the endothelial NOS (eNOS) activation in the brain cell.[4] Here, eNOS is a family of enzymes catalyzing the production of NO from L-arginine. Therefore, it is thought that nitrogen oxides (NOx) such as NO, nitrite (NO 2 ), and nitrate (NO 3 ) produced from plasma source and N 2 O gas can be expected of the improvement of the
hypoxic ischemic encephalopathy.
3. Acknowledgments The authors thank T. Yoshikawa, R. Tanaka, S. Shigekuni (Plasma Life-science Innovation Team, Department of Medical Engineering, Tokyo City University, Japan) for technical assistance. This study was supported by a Grant-in-Aid for Scientific Research on Innovative Areas (No. 24108010) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.
[1]
T. Hirata, C. Tsutsui, A. Mori, T. Kanai, Y. Kudo, T. Izawa, M. Iwashita, XXXIIth International Conference on Phenomena in Ionized Gases (ICPIG), Iasi/Romania, (2015) P4.63 [2]
T. Hirata, T. Kishimoto, C. Tsutsui, T. Kanai, A. Mori, Jpn. J. Appl. Phys. 53 (2014) 010302. [3]
C. Tsutsui, M. Lee, G. Takahashi, S. Murata, T. Hirata, T. Kanai, A. Mori: Jpn. J. Appl. Phys. 53 (2014) 060309. [4]
Brain Res., 554 (1991) 186. Topic number: 17 162
XXXIII ICPIG, July 9-14, 2017, Estoril/Lisbon, Portugal
Excitation, recombination and dissociation of molecular cations by electron-impact in cold plasmas: Application to H 2 + , HD + , BeD + and BF +
N. Pop 1,2 , J. Zs. Mezei 1,3,4,5 , F. Colboc 1 , Y. Moulane 1,6 , S. Niyonzima 7 , M.D. Epée Epée 8 , O.
Motapon 9 , F. Iacob 10 , R. Boata 11 ,V. Laporta 1 , K. Chakrabarti 12 , J. Tennyson 13 , I.F.Schneider 1
1 LOMC, CNRS, Univ. du Havre, France, 2 Politehnica Univ. Timișoara, Romania, 3 LAC, CNRS, ENS Cachan and Univ. Paris-Sud, Orsay, France, 4 LSPM, CNRS, Univ. Paris 13, France, 5 INRHAS, Debrecen, Hungary, 6 LHEPA, Cadi Ayad Univ., Marrakech, Morocco, 7 Univ. de Burundi, Bujumbura, Burundi, 8 Univ. of Douala, Cameroon, 9 Univ. of Maroua, Cameroon, 10 West University of Timișoara, Romania 11 Romanian Academy, Timișoara, Romania, 12 Scottish Church College, Calcutta, India, 13 University College London, UK.
Reactive collisions between electrons and molecular cations have a major role in the ionized gases kinetics. Using the
Multichannel Quantum Defect Theory, cross sections and rate coefficients have been obtained for different reactions induced by electrons on H 2 + , HD + , BeH + and BF
+ in natural, laboratory and industrial ionized media.
Introduction Dissociative recombination (DR), (ro)vibrational excitation (VE) and de-excitation (VdE), and dissociative excitation [1,2]: AB +
i + ,v i + )+e - → A+B, AB + (N
+ ,v f + )+e
- , A+B
+ +e - , are the dominant elementary processes in numerous cold ionized media. The Multichannel Quantum Defect Theory (MQDT) has been employed for computing state-to-state cross sections and Maxwell rate coefficients relevant for the kinetic plasma models.
In order to model and diagnose the low-temperature fusion edge plasmas, a complete database for electron-impact collision processes is required for molecular species
containing beryllium and hydrogen. We have expanded our studies on BeH +
[3,4] to BeD + and BeT + cations. Figure 1 shows as an example the Maxwell rate coefficients for the lowest states (v i +
+ , significantly dependent on the initial vibrational level of the molecular ion: Indeed, this figure illustrates the dominance of the DR, while the VdE, clearly higher than the VE, becomes progressively important for high initial vibrational levels of the target. The electron impact processes on BF + are
important in the plasma ion implantation technique [5]. The calculated rate coefficients have revealed that the vibrational transitions in this case are more important than the dissociative recombination. And finally, in order to describe the chemistry of the cold environments involved in the history of the early Universe, in the interstellar molecular clouds and in the edge of the fusion plasmas, we have extended our most recent calculations on HD + [6] and H 2 + [7] to higher energy, aiming to provide a complete state-to-state collisional data-base for the hydrogen molecular cations.
Fig.1. Dissociative recombination (DR, thick line), vibrational excitation (VE, thin lines) and vibrational de- excitation (VdE, symbols and thick lines) Maxwell rate coefficients of first excited (v i +
+ in its electronic ground state. For VE, since the rate coefficients decrease monotonically with the excitation, the lowest final vibrational quantum number of the target is indicated only, and the lower panels extend the range down to 10 −14
3 /s.
In the case of the benchmark ions H 2 +
+ , our
reaction rates and cross sections have been thoroughly compared with those measured, mainly in the heavy-ion storage rings [2].
[1] I. F. Schneider, invited topical talk at this conference. [2] I. F. Schneider, O. Dulieu, J. Robert, Proceedings of
Conferences 84 (2015). [3] S. Niyonzima et al., ADNDT (2017), in press. [4] V. Laporta et al, PPCP 59 (2017) 045008. [5] J. Zs. Mezei et al., PSST 25 (2016) 055022. [6] O. Motapon et al, Phys. Rev. A 90 (2014) 012706. [7] M. D. Epée Epée et al, MNRAS 455 (2015) 276.
1 163 XXXIII ICPIG, July 9-14, 2017, Estoril/Lisbon, Portugal
Measurements of nitrogen and oxygen
2 /Ar sputtering plasma for fabrication of high-mobility amorphous In 2 O 3 :Sn films
Masaharu Shiratani P 1 P , T. Takasaki 1 P , H. Wang 1 , K. Matsushima 1 , H. Seo
1 , K. Koga 1 , K. Takeda 2 , M. Hori 2 , and N. Itagaki 1 P
P
P
P
P
Aiming at clarifing effects of nitrogen on a-ITO film growth in N 2 /Ar sputtering plasma, we measure absolute density of nitrogen and oxygen atoms in the plasma. X-ray diffraction analysis show that ITO film is changed from polycrystalline to amorphous by introducing N 2 into the deposition atmosphere. Electron Hall of a-ITO films increases from 14 to 55 cm 2 /Vs with increasing N 2 /(Ar + N 2 ) from 1.5 to 5%, whereas the absolute density of nitrogen atoms in the plasma increases from 1.2×10
10 to 7.9×10 10 cm
-3 . Since the nitrogen composition ratio of a-ITO films is almost constant for N 2
2 ) of 1.5 – 5%, adsorption/desorption behavior of nitrogen atoms on the growing surface probably brings about changes in film properties.
Amorphous In 2 O 3 :Sn (a-ITO) has attracted attention because of the advantages such as surface smoothness, high etching rate, and low internal stress. However, the mobility of conventional a-ITO films, which are generally fabricated by lowering the deposition temperature (<150 o C), is much lower than that of polycrystalline ITO films, limiting the use of a-ITO films in practical devices. We have recently developed a new fabrication method of a-ITO films with a high mobility of 61 cm 2 /Vs. Here, aiming at clarifing effects of nitrogen and oxygen atoms on a-ITO film growth, we measure the absolute density of nitrogen and oxygen atoms by vacuum ultraviolet absorption spectroscopy (VUVAS) [2].
ITO films were fabricated on quartz glass substrates at 150°C by radio-frequency (RF) magnetron sputtering. N 2 /(Ar + N 2 ) of 0–10% was used. The total gas pressure was 0.9 Pa. The supplied RF power was 100 W. Absolute density of nitrogen and oxygen atoms were measured by the VUVAS method.
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